1. Field of the Invention
This invention pertains to elevated cableway systems used in mass transit systems and the like, and, more particularly, to an improved cableway for such systems.
2. Description of the Prior Art
Many types of elevated cableway systems have been used in or proposed for mass transit systems. One such system is disclosed and claimed in U.S. Pat. No. 4,069,765 issued Jan. 24, 1978 to Gerhard Mxc3xcller. This system is neither a suspension, or cable stayed bridge nor an aerial tramway. Consequently, not all standard design criteria are necessarily applicable to the system in the Mxc3xcller ""765 patent.
Thus the Mxc3xcller ""765 patent discloses a non-standard approach and FIGS. 1-5 of the present application correspond to FIGS. 3-7 of the Mxc3xcller ""765 patent. FIG. 1 illustrates in gross an elevated cableway system 10 in which vehicle 12 travels along track cable systems 14 suspended from catenary, or support cable 16. As shown in FIGS. 2-3 and 5, track cable systems 14 comprises locked-coil steel cables 14a-d and catenary cable system 16 comprises locked-coil steel cables 16a-b. Returning to FIG. 1, a plurality of pylons 18 elevate and support track cable systems 14 and catenary cable system 16 between the termini 20 of system 10. Track cable systems 14 and catenary cable system 16 are preferably anchored to ground 19 to sustain horizontal cable forces and transmit them to ground 19.
One of Mxc3xcller""s basic approaches is illustrated in FIGS. 1-2. Stress loads associated with the xe2x80x9csagxe2x80x9d in track cable systems 14 and catenary cable system 16 caused by the weight of vehicle 12 were a problem for cableway systems at the time Mxc3xcller filed the ""765 patent application as shown in FIG. 1. Mxc3xcller proposed, as disclosed in the ""765 patent, to address these problems by pre-tensioning, or pre-stressing, track cable systems 14 so that track cable systems 14 levelled under the weight of vehicle 12 as shown in FIG. 1.
Part of Mxc3xcller""s proposed design included new cross-ties 15 and hangers, or spacers, 7 for suspending track cable systems 14 from catenary cable system 16. These cross-ties 15 and hangers 7, which were new at the time, are illustrated in FIGS. 2-3. Through this suspension system, track cable systems 14 were tensioned as described above and, consequently, xe2x80x9cbowedxe2x80x9d upward when not weighted by vehicle 12. This approach has worked well and is incorporated in the present invention as set forth below.
Mxc3xcller also proposed tying track cable systems 14 and catenary cable system 16 together between pylons 18 at points 22 as shown in FIG. 4. Mxc3xcller tied the cables with force equalization plate 24, in cooperation with clamping plate 26 and wedges 28. Force equalization plate 24 also improved the distribution of load stresses in the cableway system and, in combination with tensioning track cable systems 14, substantially advanced the art.
Mxc3xcller also adopted the pylon structure earlier disclosed in U.S. Pat. No. 3,753,406. As set forth in column 1, line 65 to column 2, line 3 of the ""765 patent, it was thought the pylons in such a system must be xe2x80x9cstiffxe2x80x9d. It was though that xe2x80x9cself-aligningxe2x80x9d or xe2x80x9cself-adjustingxe2x80x9d pylons would introduce undesirable longitudinal shifting between the catenary and track cables. However, we now know that xe2x80x9cself-aligningxe2x80x9d or xe2x80x9cself-adjustingxe2x80x9d pylons produce substantial design benefits provided measures are taken to minimize or eliminate longitudinal shifting.
Some problems also appeared in implementing Mxc3xcller""s design despite its great advance over the art. For instance:
(1) catenary cable system 16 was strung over rollers on the top of pylons 18 and began to wear from the movement across the rollers as vehicle 12 traversed the cableway;
(2) the design of the equalizer plate 24 could also cause problems by kinking cable elements 16a-b, and 14a-d, under some circumstances; and
(3) cable elements 14a-d were required to have upper surfaces engageable by the wheels of the vehicle because the equalizer plate did not provide for such engagement.
It further came to be realized that load stresses could be better distributed through redesign of the force equalizing assembly as well as the hangers and cross-ties, particularly in light of the new pylon designs.
U.S. Pat. No. 4,264,996 by Baltensperger and Pfister describes a suspended railway system with towers that support a catenary cable atop the towers and support track cables with a xe2x80x9cstressing beamxe2x80x9d that is pivotally connected to the towers. The ""996 system is, however, distinguishably less capable than the present invention. For instance, the ""996 patent fails to grasp the catenary cable at the support on top of the tower. Therefore, as described in the ""996 patent, the cable is allowed to slip in the notches of the support. This slippage will inevitably cause wear on the cables.
Additionally, while the stressing beam gives some measure of weight redistribution at the track cable support, the fact that there is only one beam and the fact that the beam merely pivots about a single point ensures that the impact with the support of a vehicle passing over the support will not be substantially lessened. When weight is applied to one end of the beam, the other end of the beam necessarily must tilt upwardly thereby creating a ramp for a vehicle traversing the track to climb. With only a single beam, the tilt of the beam cannot be lessened until the vehicle passes each point along the beam. If the beam had secondary and tertiary beams connected to it as the present invention does, the moment about the central pivot point could be lessened in advance of the vehicle. With secondary and tertiary beams, the point of applied load is the point where the secondary beam attaches to the main beam, not the point the vehicle is passing.
It is therefore a feature of this invention that it provides an improved pylon design for elevated cableway systems.
It is furthermore a feature of this invention that the improved pylon design reduces wear on the catenary cable system by not allowing the catenary cable system to slide or role directly on the top of the pylon.
It is furthermore a feature of this invention that the improved pylon includes a new, deflecting upper saddle to support the catenary cable system while relieving stresses imposed on the catenary cable system by deflecting under load applied by the vehicle traversing the track cable system.
It is a still further feature of this invention that the improved pylon includes an improved, pivotable lower saddle to better transmit forces and distribute load stresses through the cableway system as the vehicle traverses the cableway.
It is furthermore a feature of this invention that load stresses are distributed through improved hanger and spacer designs.
It is still furthermore a feature of this invention that it provides an improved cableway system with greater lateral support for the union between the catenary and track cable systems by providing improved force equalizing assemblies.
It is still furthermore a feature of this invention that it provides an alternate force equalizing assembly that reduces wear on the catenary cable system and the track cable systems by allowing the cables to controllably yield relative to one another as force is transferred between them.
The features described above, as well as other features and advantages, are provided by an improved cableway system that includes a pylon, an upper saddle, and a lower saddle. The pylon includes a base pylon, and the lower saddle is mounted to the base pylon from which a track cable may be strung. The upper saddle, from which a catenary cable system .may be strung, is movably mounted to the base pylon to deflect in response to the weight of a vehicle traversing the track cable systems.
The improved pylon also includes in some embodiments a new lower saddle including a main beam pivotally mounted at the center of its longitudinal axis to the pylon for rotation in a first vertical plane. A pair of secondary beams are each pivotally mounted at the center of its longitudinal axis to the main beam substantially at a respective end of the main beam for rotation in the first vertical plane. Four tertiary beams are each pivotally mounted at the center of its longitudinal axis to one of the respective secondary beams substantially at a respective end of the one secondary beam for rotation in the first vertical plane. Eight suspension rods are each pivotally mounted at one of its ends to one of the respective tertiary beams substantially at a respective end of the one tertiary beam for rotation in the first vertical plane. The other end of each suspension rod is pivotally connected to a cross-tie at the center of the cross-tie""s longitudinal axis for rotation of the cross-tie in a second vertical plane that is perpendicular to the first vertical plane. The cross-tie supports the second cable. Four shock absorbers are each pivotally mounted at one of its ends to one of the respective tertiary beams, and the other end of each shock absorber is pivotally connected to a cross-tie near another end of a suspension rod that is connected substantially at the other end of the tertiary beam to which the one end of the shock absorber is connected. Four bracing rods are each pivotally mounted at one of its ends to a cross-tie near a lower end of a first suspension rod. Another end of each bracing rod is pivotally connected to a cross-tie at a lower end of and near a second suspension rod that is connected to an opposite end of a tertiary beam from which the first suspension rod hangs.
The improved cableway system also includes improved hangers and cross-ties comprising a hanger member suspended from the catenary cable system by one end thereof. A cross-tie is pivotably mounted to the hanger member at the end distal to the catenary cable system. A track cable guide is affixed to the cross-tie, and a power rail guide is mounted to the cross-tie.
A force equalizing assembly for joining the catenary cable system to the track cable systems midway between the pylons is also provided to equalize the tension between the support and track cable systems. The assembly includes a force equalization plate having at least three parallel channels formed along the length of a surface thereof is provided for accepting the support cable in the center channel and the track cable systems in the outer channels. The channels are shaped to approximate one-half of the respective cable circumferences, except that the ends of the channels are flared outwardly. The channeled clamping plate has at least three parallel channels formed along the length of a first surface thereof is provided for accepting the support cable in the center channel and the track cable systems in the outer channels. The channels of the clamping plate are shaped to approximate one-half of the respective cable circumferences, except that the ends of the channels are flared outwardly. The channeled clamping plate has a second surface opposite the first surface that is adapted for engagement by the wheels of the cable car. The channeled surfaces of the force equalization plate and the clamping plate are complementary such that the plates may be assembled about the cables for frictionally locking the cables within the respective channels to equalize the tension in the support and track cable systems. The respective flared ends of the channels in the assembled plates form a frusto-conical cavity in each end of the assembly about each of the cables for reducing wear on the cables by the ends of the plates.
In another improved embodiment of the force equalizing assembly, the cables of the catenary cable system and the track cable systems are grasped about their circumferences by cable connections of a system of cable encasing members. The cables are thereby connected through the cable connections to a frame of the system of cable encasing members for distributing forces among the cable systems. The force equalizing assembly is adapted to accept connection of cables both from angles acute to and parallel with the longitudinal axis of the frame.
In another improved embodiment of the force equalizing assembly, a catenary cable system clamp grasps the catenary cable system and a plurality of track cable system clamps grasp the pair of track cable systems. The track cable system clamps are yieldably attached to the catenary cable system clamp to provided controlled force distribution between the cable systems. The top surface of the plurality of track cable system clamps is adapted for engagement by the wheels of a vehicle traversing the elevated cableway system.